Until marijuana is legally sold in Ohio, state law gives patients an affirmative defense from prosecution for possessing marijuana and paraphernalia.

But the defense only applies if the patient has obtained a note from his or her doctor indicating the patient meets a few criteria and the marijuana would be permissible under state law, which does not permit smoking marijuana or growing it at home.

"The board recommends that physicians consult with their private legal counsel and/or employer for interpretation of the legislation," the board said in a statement released Friday.

The statement noted state law requires doctors have a special certificate, not yet available, to issue a "written recommendation" for medical marijuana. But the board didn't indicate a difference between a recommendation for an affirmative defense and a recommendation to register a patient in the yet-to-be-established program. That leaves open the interpretation that physicians can't write recommendations until certified.

The law allows people with about 20 medical conditions to use and buy marijuana if recommended by a doctor. It also grants immunity to doctors from civil liability, criminal prosecution and discipline from the state medical and pharmacy boards for advising patients use medical marijuana, discussing the drug with them or monitoring a patient's treatment with marijuana.

The law went into effect Sept. 8, but the Ohio State Medical Association advised physicians to wait to act on affirmative defense letters until after the board weighed in.

State medical board spokeswoman Tessie Pollock said the board will review a medical marijuana related complaint as they would any other. Pollock said the board would consider whether someone violated state law, including the immunity provision.

By September 2017, the board must decide how doctors become certified to formally recommend medical marijuana.

Sen. Dave Burke, a Marysville Republican who worked on the law, said Thursday the law was intended to let patients use medical marijuana as soon as it took effect and further guidance from the medical board at this time was unnecessary.

"Willing physicians are in the free and clear," Burke said, noting doctors will have to treat marijuana as a controlled substance under state law. "The affirmative defense was meant to allow for a quick transition for folks who need this product sooner than later."